audit: push loginuid and sessionid processing down

Since we are always current, we can push a lot of this stuff to the
bottom and get rid of useless interfaces and arguments.

Signed-off-by: Eric Paris <eparis@redhat.com>

diff --cc drivers/tty/tty_audit.c
Simple merge

diff --cc include/linux/tty.h
Simple merge

diff --cc kernel/audit.c
Simple merge